The number of Syrian refugees in neighboring countries has more than tripled since June to over 300,000, and by the end of the year that number will more than double again, the UN refugee agency warned Tuesday.

"The latest figures show a total registered population of more than 311,500 Syrian refugees in the four countries (Jordan, Lebanon, Turkey and Iraq). You might recall there were about 100,000 as of June," UNHCR spokesman Adrian Edwards told reporters in Geneva.

"Many refugees and the communities hosting them are already running out of resources," he said, stressing the need for more funds.

Last week, the UNHCR and several other humanitarian organizations launched a joint appeal for $487.9 million (379.2 million euros) aimed to help up to 710,000 Syrian refugees in neighboring countries by the end of the year.

"Another factor is the upcoming onset of winter temperatures across the region in just a couple of months time. We're in a race against time," Edwards said.

The already strained refugee host countries will be further strained in the months to come, according to UNHCR, which expects the number of Syrian refugees in Jordan to leap from nearly 103,500 now to some 250,000 by the end of the year.

In Turkey, there were meanwhile over 93,500 Syrian refugees registered as of Monday, but several thousand are also residing outside the current 13 camps, UNHCR said, predicting the number of Syrian refugees in the country could surge to 280,000 by year-end.

The situation is also dire in Iraq, where some 33,700 Syrians have been registered as refugees so far, including 4,263 in the past week alone, and where the UNHCR foresees that up to 60,000 Syrians may be in need of protection and assistance by the end of the year.

In Lebanon, meanwhile, the UN agency said the current tally of 80,800 Syrian refugees is expected to leap to 120,000 by the end of 2012.

The host countries say they are overburdened by the refugees and are struggling to find solutions.

Last month Jordan appealed for $700 million to help support the refugees, explaining that the country couldn't afford to pay for the services and supplies the refugees required.

Also last month, Iraq announced that it was lifting a hold on Syrian refugees from entering the country that was previously imposed, but would not allow young men to enter over what it claims were security concerns.

In August, Turkey proposed the establishment of "safe zones" inside Syrian territories "liberated" by rebel fighters for refugees to set up camps, but the plan never materialized.

Do Syria's neighboring countries have the resources to look after this number of refugees? Are 'safe zones' a viable idea? Leave us your comments below!